Bear in mind that the population at the time was acutely aware of the contending jurisdictions (PA vs. VA), but subsequent generations lost knowledge of the historical details.In addition, the men who lived long enough and had enough active-duty service to apply for Pensions, also did not recall enough of the details to be quite historically exact when explaining service.
Not to mention that the Pension Bureau folks who were reviewing the applications also did not understand that a person who lived in one place from 1770-1800 might have served in several differently-defined militia organizations.
For examples, see the rundown of soldiers' names and the units they claimed to be in at the Fort Laurens website.You will find a John Evans claimed to have been in a PA militia organization who was probably actually the John Evans called "Captain Jack," of Monongalia County, (West) VA militia -- he lived across the river from present-day Morgantown, close to the boundary with PA.
I've seen this sort of confusion in several pension applications.If you want to look up an example, check out the declaration for pension of Henry T. Franks (available free from HeritageQuest if your library subscribes, maybe you can even log in to the site using library card or driver's license) (Also available on Ancestry.com, possibly through your library if it subscribes, but usually only by using the library's own computer internet connection).
It is also possible that DAR got his provable actual service wrong.Would not be the first nor the last time.